The invention discloses a quick-changing multi-spindle tool. The quick-changing multi-spindle tool comprises a mounting seat, a plurality of force output shafts and a power unit; the plurality of force output shafts are detachably and movably mounted on the mounting seat; the power unit is also mounted on the mounting seat; the power unit can also drive the plurality of force output shafts to rotate; in addition, a cooling passage for a cooling liquid to flow is also formed in the mounting seat. According to the quick-changing multi-spindle tool, the force output shafts can be singly and rapidly assembled, disassembled and changed in a labor-saving manner so as to effectively enhance the mounting and changing efficiency to be beneficial for assembling and maintaining the quick-changing multi-spindle tool; and in addition, as the cooling passage for the cooling liquid to flow is also formed in the quick-changing multi-spindle tool, the plurality of force output shafts in working can becooled to prevent the quality of a machined product from being affected due to over-high machining environment temperature and prevent the force output shafts from being deformed and so on due to over-high temperature; and therefore, the service life of the quick-changing multi-spindle tool is prolonged.